MONTERAY PICTURESMira Sorvino and Dermot Mulroney in "Trade Of Innocents."

Mira Sorvino has been busy.

Over the past decade, she has made films for Hollywood studios and TV networks. She has travelled the world as an activist, fighting to end violence against women and the sex-trafficking of children.

She's a multitasker.

Like now, when, in the middle of our long phone conversation, her voice suddenly gets muffled, there are some gurgles in the background and, finally, the wet thud of something tossed aside.

"Yes," she says, with a laugh. "I was changing a diaper while we were talking."

All of which goes to explain why she hadn't been on movie screens that much lately.

And why she's on them again now.

Her latest movie, "Trade of Innocents," is a drama about a couple who, after their own family tragedy, go to Asia to help others. Husband Dermot Mulroney aids local police in breaking up sex-trafficking rings; Sorvino guides the rescued children through therapy sessions.

The movie hits the usual thriller notes -- victims in jeopardy, villains running through crowded streets, tense standoffs with cocked guns. But the film's real purpose is advocacy -- to inform people about a horrible problem, and to encourage diplomats and local agencies to combat it.

"I started working with Amnesty International a while ago on violence against women, and human trafficking was one of the topics," says Sorvino, 45. "I was horrified to learn slavery still exists, that it's a $32 billion a year criminal enterprise. ... It's growing faster than our efforts to stem it. Right now, only one in a hundred victims is ever saved."

Which, of course, doesn't mean you don't try. Since Sorvino also became the UN's Goodwill Ambassador for anti-trafficking efforts in 2009, she's gone around the world and to U.S. state legislatures. "Trade of Innocents" is her second movie on the subject; in 2005, she also made the bluntly named "Human Trafficking" for television.

"It's not like I only do anti-trafficking movies," she says. "I waited seven years to do another one. But it's an important subject; there are kids being sold on the streets right now, and in America, too.

"Honestly, there is nothing more angering than thinking about one of these adorable little people who've been used that way. You look in their faces, honestly, you just can't stand the world."

Kind, compassionate

Sorvino's passion comes purely from empathy, a quality any good actress has in abundance; personally, she grew up safe and sound in Tenafly, the daughter of actor Paul Sorvino. It was, she says, an idyllic neverland of broad lawns and let's pretend.

"I had a wonderful, protected childhood," says Sorvino, whose best friend was Hope Davis. "We were always outside, using our imaginations, putting on plays, playing ghost-in-the-graveyard, catching frogs. I took ballet, rode a lot. It was a very normal, very nice, American bringing up."

Early on, Sorvino says, "I knew I wanted to be one of the As -- an astronaut, an anthropologist or an actress." But although -- or perhaps because -- her parents knew what the last profession entailed (her mother, Lorraine, had acted as well), they forbade it.

"I got bitten by the stage bug in school -- it was just this rush being in front of an audience," she says. "But professionally, no, no, my parents said absolutely not. And I'm really glad they did, because I had a childhood. Once in a while, I'll let my kids do an extra part in one of my movies, but becoming a full-time professional -- I think it really robs kids of a free time, a carefree time, that will never, ever come again."

So Sorvino graduated from Dwight-Englewood School, and went on to Harvard where -- no slouch -- she majored in East Asian Studies, learning Mandarin and graduating magna cum laude.

GETTY IMAGESMira Sorvino brandishes her Oscar after winning the award for best supporting actress for her role in the film "Mighty Aphrodite" at the 68th Annual Academy Awards 25 March in Los Angeles.

"I wanted to give myself an alternative," she says. "I knew I liked acting, but I wanted to see if there was anything else I wanted to do and know that I had a Plan B, so I really focused on the academics. But I still did like five productions, and sang and directed a play. And after I got out, I started missing the performing pretty hard."

She started going to auditions and landing small parts, several of them with good directors -- she's in Robert Redford's "Quiz Show," Whit Stillman's "Barcelona."

It was her performance in Woody Allen's "Mighty Aphrodite," though -- as Linda Ash, a helium-voiced hooker with yards of legs -- that made her a sudden star and won her an Academy Award for best supporting actress. (And also made her speech a perpetual item in Best Oscar Moments lists when the camera cut to papa Paul, sitting in the audience, sobbing with joy as she accepted.)

"That whole night was dreamlike," she says now. "It was unbelievable, and such a gift -- it took me overnight from this unknown actress to someone being offered all these movies."

Independent choices

Like Linda, though, she probably said "yes" a little too often. Although she chose to work with interesting people like Susan Seidelman, Wayne Wang and Paul Auster, many of the indie projects went nowhere.

Her few studio films seemed like odd follow-ups: the horror movie "Mimic," in which she battled mutant cockroaches, or the thriller "The Replacement Killers," which felt more like then-boyfriend Quentin Tarantino's idea.

Sorvino was still good in whatever she chose -- she did a lovely job as the Hollywood star in TV's "Norma Jean & Marilyn," and was hilarious as a daffy Californian in "Romy and Michelle's High School Reunion." But her career got off the main road and has never quite found the on-ramp again. Most of her movies now slip through art houses quickly, if they don't go directly to DVD.

"It's getting harder and harder," she admits. "There's so much independent product out there, and the real bummer is, even when you get distribution, there's never enough money to pay for ads. Opening weekends are brutal, it's a competition to the death."

It's meant that some of Sorvino's best performances -- like the brassy-but-vulnerable Bronx woman she played in this year's under-the-radar "Union Square," or the working-class, desperately conflicted birth mother in 2009's "Like Dandelion Dust" -- haven't been seen by nearly as many people as they should have been.

When they get discovered at all, it's often by insomniacs, channel-surfing through the cable choices.

But don't feel sorry for Mira Sorvino. She doesn't.

To begin with, whenever she's had the choice, she's always opted for foreign films and indie dramas. And she's always known, from the minute she's signed on to them, that they weren't obvious people-pleasers (like "The Grey Zone," grim even for Holocaust dramas, which "some reviews criticized us for even making").

Sorvino also knew her most personal choice -- to get married, to actor Christopher Backus in 2004, and start a family -- was probably going to "lead to a lot of gaps, professionally."

"I've had four children in seven years," she explains. "I've been pregnant a lot. And, you know, that takes you away. You really can't work when you're visible, and afterward, you need time off, you need to recover, you need time with your baby ...

"I still need to work -- I can't retire -- and I still want to find good pieces to work on. But it's more important to be a presence in my children's lives and that complicates the equation."

Complicates it, but also deepens it.

For example, her new perspective has only intensified her affection for independent films -- not just because of the shorter shoots, which give her more time with her kids, but because of the far more vital commitment the movies demand when she's actually on the set.

"You don't feel like you're at a factory, designing a car, figuring what options you have to add to get a buyer -- 'Oh, it needs to have a sun roof, it needs four-wheel drive,'a" she says.

"You're not following a pattern with these films. You're taking risks."

Tackling social issues

She's also become more involved in social issues. "I'd lost the chance to delve into those things when I first started acting," she says. "And now, with the U.N., I spend a lot of time researching and interviewing survivors of trafficking, and lobbying governments and state legislatures ... So I have a sort of double life, doing that and doing movies. Although my biggest role is still being a mother."

And having these extra roles -- as a parent to four young children, as an advocate for millions of others she'll never even meet -- has given Sorvino a stable base and a serious purpose that she probably wouldn't have had if she'd merely stayed a star.

"It's a messed-up business," she says frankly. "Our obsession with the superficial, with what's flashy -- the values are all kind of cockeyed, and we're all part of this culture that keeps promulgating them. ... I remember meeting some people for the first time and they said, 'Oh, we just saw you in the Star -- they had a big picture circling all the cellulite on your thighs!'"

She laughs.

"I was horrified," she says. "But I know they didn't mean anything by it. I'm sure they thought, oh, actors, they're used to it ... But, really, it can be very hard. You get this pressure as an actress, oh, you're supposed to be this iconic ideal girl. You're supposed to be sexy, desirable, whatever. But you need to be able to separate from your public image and what people think you should be like. And you have to remember what's important, and hold on to who you really are."